Calvin Cycle

the ATP needed in the Calvin cycle comes from

both cyclic and noncyclic photophosphorylation

a C3 plant

can only fix carbon using the Calvin cycle

In hot and dry conditions, the process of ___________ can reduce the efficiency of photosynthesis by 25-50%

photorespiration

The C4 pathway has a cost to plants, because the conversion of _________ to PEP requires the expenditure of ATP

pyruvate

RuBP stands for ____________ 1,5 bisphosphate

ribulose

What is the name of the enzyme that incorporates CO2 into organic matter during the Calvin cycle?

rubisco

What is the name of the enzyme that catalyzes the addition of CO2 to a molecule of phosphoenolpyruvate?

PEP carboxylase

Both PEP carboxylase and rubisco can fix carbon dioxide. However, PEP carboxylase:

does not bind oxygen

After it is transported into the cytoplasm, the G3P made during photosynthesis is usually used to synthesize fructose 6-phosphate and glucose 1-phosphate, which can be used to form

sucrose

most plants transport the fixed carbon in the form of the transport sugar

sucrose

What is the relationship between photosynthesis and cell respiration?

- The products of cell respiration are the reactants of photosynthesis - the products of photosynthesis are the reactants of cell respiration

Photorespiration is considered "wasteful" because

- reduces the ability of a plant to make carbohydrates - it reduces the yield of photosynthesis

______ plants avoid water loss by closing their stomata during the day and opening them at night

CAM

Which of the following happens to the molecule formed by the addition of carbon dioxide to ribulose bisphosphate?

It is immediately split into 2 more stable three carbon molecules

Photorespiration has which of the following effects on photosynthesis?

It reduces the yield of photosynthesis

What are phases of the Calvin Cycle?

1. carbon fixation 2. reduction and carbohydrate production 3. regeneration of ribulose bisphosphate

How many ATP molecules are needed to synthesize two G3P molecules

18

Typically, it is considered that the net gain of the Calvin cycle is _____ molecules of G3P

2

How many molecules of CO2 need to be bound to molecules of RuBP to produce 12 molecules of PGA in the Calvin cycle?

6

Why do hot and dry conditions favor photorespiration?

Because plants close their stomata, inhibiting CO2 uptake and increasing O2

Why does CO2 enter CAM plants at nightime?

Because the stomata of CAM plants are only open at night

Plants that only fix carbon using the Calvin cycle are also known as ______ plants

C3

The Calvin cycle is also known as _____ photosynthesis because the first intermediate of the cycle contains three carbon atoms

C3

Which type of plant does carbon dioxide capture occur in one cell, and decarboxylation occur in an adjacent cell?

C4 plants

What is the primary output of the Calvin Cycle?

G3P

in C4 photosynthesis, carbon dioxide is stored in the form of an organic acid and can be released in a different _____ or at a different ______ to keep the level of carbon dioxide high relative to oxygen

cell; time

The enzyme rubisco has more than one activity. Because of this, most plants also perform _________, which consumes oxygen and liberates carbon dioxide. This process can lower the net benefit from photosynthesis

photorespiration

Do C4 and CAM plants use C3 photosynthesis?

yes

True or false: glucose is the primary output of the Calvin Cycle

false

what plants are C4 plants?

sugarcane sorghum corn